how long do propane rubber hoses last?

just purchased 2001 cardinal.
hoses look a little brittle. are there different types of hoses. someone told me not to use the hose with green connector, use the old brass connector.
also how about changing regulator

You should give them a good look. My previous TT I replaced top 2 when I changed to auto-change regulator. Current TT, I had to change lower hose at 3 years old, as a squirrel decided it was wonderful for gnawing on.

If they're no longer flexible I'd replace them. Last year I replaced the regulator and hoses in about 30 mins. It was cheap enough and I'd rather not risk a gas leak when on the road.

Go by condition of the hoses. Have they been kept under a propane tank cover? If they look questionable, replace them. Want real peace of mine? Replace them anyway!!

i would give them a good look over, they can get old and brittle, but most regulators are equipped with a safety to severely limit flow if there's a load on the system when you turn on the tank, also your trailer should have a (working) propane detector.. i would only change them if they look physically deteriorated or give indication of a leak.. save your money for other stuff.

Its your safety and time if something fails. Itsyour choice is a few bucks is, worth your knowing the condition

My hoses are over 10 years old. If they're not cracked/dried out, I wouldn't worry about it.